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Air compressor woes

mitchntx

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Joined
Jun 11, 2006
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Location
Granbury
For the last few months I've been noticing my 20 year old air compressor seems to be a bit sluggish. Takes forever to recover and cycles on really quickly.

During the cold snap in december, I had a drain line freeze and bust. As with my luck, it was on the pressure side of the ball valve. I don;t know how long it had run with a minor air leak. Changed the oil while I was in it.

Got that fixed and noted the cut-off air pressure was 135psi. :eek2:
Adjusted the cut-off and recover pressures. to 120 and 85.

A few days ago, I was headed to work and heard an awful screeching noise from the shop. Ran to the breaker box and killed the compressor. Great ... compressor is toast. :giveup:

I looked on-line and it would take $12-1500 to replace it. :headbang:

I checked the oil. It was clear and clean.
I removed the belt and spun the motor up. It ran smooth.
I spun the flywheel. It was free and easy to move. I could hear the compression stroke and the puff of air.

Only thing left is the switch, cut-off assembly. That would attribute the sluggish recovery which was actually over-pressurization.

The switch arrived today. I had to cobble a few lines and fittings together as it wasn't like for like. Wiring was different and was just one trip to the hardware store for a new relief valve and some compression ferrules.

Seems to work as before. But as a precaution, I'll probably leave the compressor breaker shut off till I can spend a day out there and have a chance to cycle the compressor a few times.

Best I can surmise is that the screeching I was hearing was either the belt slipping on the flywheel straining against the high pressure or the bearings inside the compressor itself for the same reason.

I don't hear it now, thanks goodness.
 
Joined
Jan 25, 2005
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Cypress Tx
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David
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Probly belt slipping , no shop tools are powered up when I'm not in my shop . That makes it too easy for a major screwup . My beer fridge is the only thing left on .
 

OldTLSDoug

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Mitch, glad you got it sorted. I used to turn mine off, it doesn't cycle much unless I am using the bike lifts.
 
Joined
Nov 20, 2012
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Waco
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Rob
I'm on the verge of buying a new unit. I've been following along the new scroll compressor that Eastwood has out. supposed to be really quiet and very efficient. I think around 12 CFM @ 40 and 90 PSI with a max of 145 PSI. I've seen some bigger units that go up to 175 and a little more CFM rating down low but they are usually two stage setups and noisy as heck. My friend down around Killeen has one setup and after running it and letting it cycle he recorded it at 66 db when pressuring up and even though its only got a 30 gallon tank he says the recover time is next to nothing.

Decisions, decisions....
 

Texas T

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I've been following along the new scroll compressor that Eastwood has out. supposed to be really quiet and very efficient.
The scroll compressors seem to be what is being used on all the modern muscle cars these days, and my roots style 6-71 blower just sits in the garage collecting dust.
 

mitchntx

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Granbury
Hadn't lost a psi since 1400 ...

Pros and cons to adding capacity ...

If I tapped in a 60 gallon tank or another 80 gallon, would I be asking too much of the single stage compressor?
 
Joined
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Rob
Hadn't lost a psi since 1400 ...

Pros and cons to adding capacity ...

If I tapped in a 60 gallon tank or another 80 gallon, would I be asking too much of the single stage compressor?
What HP rating and CFM rating on the unit?
 
Joined
Mar 3, 2005
Messages
2,103
Location
Tyler, Texas
My Ingersoll-Rand 60 gallon has a single stage pump and does just fine. I wouldn't think the increase in tank size would matter that much providing you have an oil-filled cast iron pump unit.

I second a loose belt causing the noise.
 

mitchntx

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Jun 11, 2006
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Location
Granbury
WMC must go thru a lot of air.......
Mostly hot ...


Years ago I had an oil-less 30 gallon compressor that I had daisy chained two 6-gallon portable tanks with standard shop quick connects.

Added capacity was great when rotating tires and such and it was very handy to always have a fully charged portable air tank to use.

The compressor never failed, but it ran a LONG time in the process of recovering. But to offset that, it ran half as often.

While troubleshooting my compressor, I was just wondering if I could do it on a larger scale.

Once the sleet stops, I'll pull the specs off the compressor and post them.
 
Joined
Nov 20, 2012
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Waco
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Rob
I have one of the HF 25 pieces of trash hooked to a propane tank (I bought it clean and empty so don't fret fellas). I can't recall if it is 100 lb or 150 pound but its probably about 30 gallons total. I'm sure it's led to the early demise of that HF Unit. It's leaking air somewhere and right now I'm not doing anything with it to care but I figure once the new house is finished I am maybe repurpose the spare tank as a portable air tank.
 
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Apr 22, 2011
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McKinney, Texas
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Well it’s a lot better than my 20 year old Sears Roebuck compressor, it is only rated at 9.1 scfm at 40 psi and 7.1 scfm at 90 psi, doesn’t say the power of the motor, but states 120 volts and 15 amps, which would make it about 2hp. Would love to get a bigger twin stage, but don’t use it enough to justify the expense. If it ever goes bang, the replacement will definitely be bigger. No idea what size the tank is, about 3 feet long and 14 inches diameter.

Gary
 
Joined
Oct 16, 2008
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Location
Bryan, TX
I have a Jacuzzi compressor that I bought used in the mid '70s. It's one that runs constantly if it has electrical power. I think the device that stops compression is called a constant speed unloader. It came with about a 5 gallon tank and I now have it on a 60 gallon tank. In the old days, the service stations used a very small single cylinder compressor for a very large tank to operate their car lifts. Duty cycle is the key.
 
Joined
Apr 26, 2006
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Seabrook, TX
Duty cycle is the key.
If the comp and motor are rated for continuous duty cycle, theoretically they can be used to fill any size tank(s) or even direct output to a tool.
 
Joined
Oct 16, 2008
Messages
1,887
Location
Bryan, TX
A 60 gallon tank holds 60 gallons at atmosphere pressure (15 PSIA), about 400 gallons at 85 PSIG (100 PSIA) and about 540 gallons at 120 PSIG (135 PSIA). If my approximations are correct, it should take a 10 CFM pump about 14 minutes to go from 85 PSIG to 120 PSIG.
 
Joined
May 6, 2003
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1,662
Location
Ada, OK
I have 2 60 gallon single stage (?) compressors linked together. Both are about 20 years old. One a Porter-Cable bought at Lowes the other a Devilbiss. One is 7hp the other 6.5. They are both twin cylinder and could be 2 stage, possibly ported inside the head, but I doubt it. They are linked via air lines but can run separately electrically. I typically just run one at a time, but use both tanks. The volume is the key as far as I'm concerned. With just one running it doesn't cycle as often, but yes it will run longer to get the 120 gallons full. If I'm really using a lot of air like blowing something off Ill run both at the same time. They are both rated around 12cfm. I paid like $300 for the porter-Cable at Lowes. I inherited the Devilbiss.
 
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You can easily tell if they are 2 stage. One cylinder will nearly always be larger than the other. Also, the tube connecting the cylinders will have cooling fins and only one of the cylinders has an air cleaner.
 

OldTLSDoug

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When I was purchasing my compressor it was agony to decide what to buy. Ended up with a 3 cylinder single stage Husky from Home Depot. Like I said, if I am not blowing stuff and just using lifts it barely runs. I isolate my lifts since they both ooze a little air at times.

20170820_1008511.jpg


20170901_1350351.jpg
 

mitchntx

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Jun 11, 2006
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Granbury
Big compressor ... clean shop ... now yer just bragging ...

Sent from my SM-G900V using Tapatalk
 

greeneggs&ham

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I noticed that in OLDTSLDOUG's picture he has a ball valve on the tank, before air lines. All compressor systems should be like this. Leave the compressor electrically tuned on all the time. You walk out of the garage you close the ball valve. Compressor should never run when not being used because there will be no pressure loss. Addressing leaky lines and connections is for a different thread.

If you walk into your garage and have to wait for your system to pressure up, it might irritate you, but look at all the energy you have just wasted. Years ago I had a customer who's employees walked out at the end of the day and just turned the compressor off. It was a 3 cylinder piston Atlas Copco on a 160 gallon tank, with an additional 200 gallon tank inside the building. Their complaint to me was it took 15 minutes or more for the system to pressure up in the morning!...

Mitch if you put another tank in your system, just put ball valves on both tanks, they will hold pressure and your pump should cycle less often since you have more storage capacity, such as when using high cfm grinder. But the on cycle will be longer since it will have to fill more area. On small jobs just open the ball valve on your main pump/tank.

Hope this helps.

Sam
 

mitchntx

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Granbury
Thanks Sam I am ... it does, it shall, it always will. :-)

Ball valve in place, but rarely use it. It's on the back side, sheltered by a wall. Only cycle it a couple times a year or when I change the drops in my system. I oriented my compressor so that the fitting didn't get bumped accidentally. Used to build roll cages in there and wielded lengths of 1.5" DOM tubing around.

I also have a 1/4" ball valve on the drain and on my my drier.

I've concluded it doesn't make a lot of sense in adding a tank based upon my current usage. When I had a couple grinders running, then it made more sense.
 
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